Comparative Analysis of Multiple Active Bridge Converters Configurations in Modular Smart Transformer

In this paper, the quadruple active bridge (QAB) dc–dc converter is proposed to be used as a building block to implement the dc–dc stage of a smart transformer (ST). Different configurations (symmetrical, asymmetrical, and rated for voltage/power) for this converter are considered for investigation. Four different architectures of ST, including one based on the dual active bridge converter as a benchmark and three based on the QAB converter, are presented and compared in terms of cost, efficiency, reliability, and implementation complexity. As an additional contribution, different semiconductor technologies (silicon IGBT and silicon-carbide MOSFETs) are evaluated in order to verify their impact on ST application. The design for each architecture is described and the results are compared. In order to validate the theoretical analysis developed in this paper, a 20-kW prototype is built and experimented.